I swear upon my soul!
by Toesz
Summary: Genocide route Sans realises that something might be off at home, with the human roaming around. He goes back and what he finds is not pleasant at all.


**_DISCLAIMER: I do not own Undertale or any of the characters. They belong to the glorious Toby Fox._**

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Sans had a bad feeling. He wanted to shake it off lightly, but he knew that he could trust his intiution. Something terrible was about to happen. Which wasn't new for him.

He was sitting in his -magicly- snow-covered sentry station in Hotland, eating a hot dog. It tasted like paper, but he had to eat something. He knew about the human's rampage, that's why he had been worried in the first place. The other reason was his little, naive brother...

Sans wanted to be next to Papyrus in every minute of the day, but Sans was the guardian of the Underground. It was a name that he granted himself, being the only monster with his knowledge of timelines and teleporting, so he had have an eye on everything. He worked behind the scenes when danger was too big for Undyne and the Royal Guard. Man, how lucky he was that Papyrus wasn't a member! But... It would have been good to know the strong fishlady by his brother's side...

He threw away the tastless thing that he tried to forced down his throat. Why was he here in the first place?! There is no danger in Hotland, the kid is having their genocide in distant places. The hot lava made strangely reminded of the opposite. Something cold.

What if...

"What if they are in Snowdin right now?" He murmered, his voice low and filled with worry. The monsters there had enough common sense to hide... But knowing Papyrus... that skeleton would try everything in attempt to make the human good again. That bonehead...

 _Bro, you need to learn how to be a little less merciful..._

Sans did know how to teleport, however it took a couple of minutes to get to the other part of the country. Home was big, after all.

He landed at the end of the forest, just outside of the small village. His steps echoed as he was walking towards the familiar buildings.

The unharmed welcome sign looked ominous and creepily cheerful, knowing the circumstances. The second thing that caught his eyes were the footsteps. Or rather, the lack of them. The usually slippery roads were now almost entirely covered with crispy virgin snow.

How long had the monsters been inside their homes, living in fear? He had been away from them for less than a day!

As he was staring at the snowpuff in front of his slippers, he noticed an unfamiliar pair of footprints. No... these weren't unfamiliar, he had seen them before. They were just unknown in Snowdin. They were small and quite symmetrical. They looked almost like his. Are they the...

...The human's...?

He hoped he was wrong. The sinking feeling lasted for a few minutes and it was so strong, he felt his legs freezing into the snow, slowly becoming one of Lesser Dog's snow statues. _Why can't move!?_ That human wasn't merciful at all. Ironically, humans would have called them a monster, but no monster would have kill out of fun.

He closed his eyes and smashed a handful of snow on his face. Its coldness helped him collect himself. Why wasn't he moving, when his brother was in danger?

He made a cone with his hands and yelled. "Papyrus! Where are you?" But only the echos answered his call. He heard his own voice repeatedly fading in the distance, but not another voice.

Sans shook his head, drawing conclusions from this hopeless attempt. No, there's no was that his village was completely massacred like animals. Someone had to be here.

He saw that the Snowed Inn was closed, its windows had wooden boards on them. Good. So the bunnies were alive at least. He wondered if the shop was open, but... it wasn't. As a shopkeeper, the owner couldn't be attacked, but the family must have been scared to death, no wonder they rather closed it up. He decided not to freak them out by banging on their door...

Sans ran up to Grillby's. He had met no one on the street, he hadn't expected anyone anyway. He found the bar open, but the emptiness inside left a deep mark in him. He had _never_ seen it without life. Not once. Glasses left on the counter, cards on the tables, bones, where the dogs had sat... And the only music was Sans's shallow, quick breath and the howling wind's harmony, which blew the snow into the once friendly room.

"Hey, Grillbs, are you here? You've left everything here, like there was fire somewhere..." He snickered weakly. It was a feeble try, but he had to say it. He needed something familiar, like an annoyed groan or something. There was no answer and he was creeped out by the place, so he left as fast as he could.

Outside, he tried to reach Papyrus through his cell. But no one picked it up. _Come on!_

He shouted his name again, in case Pap hadn't heard it.

He was growing more and more impatient, so he just glanced inside the library, which was in the same condition as Grillby's. He knocked on other houses, not hoping to get an answer. He decided, it was better not to know if the habitants were scared or dead...

Eventually, he reached his home. He took out the key of the front door, opened it and stepped inside the warm living room. There pet rock was on the side table, a new amount of sprinkled sparkling on it.

Pap wasn't in the kitchen or anywhere on the ground floor. "Hello, Papyrus? I'm home! You're chilling in your room?" He went upstairs and loudly knocked on his brother's door, which was decorated with many colourful signs and labels. In the lack of answer, he sighed. "Okay, I'm coming in." He stepped inside to see...

...That there was not a single soul there. Not even in the wardrobe.

As desperate as he was by now, he even checked his own, always locked room. The science books greeted him with their usual cold flashbacks. Sans winced and went out of the house.

 _This is no good... Where can he be? Is he at Undyne?_

Sans put up his hood. He wasn't sure if it was actually that cold or it was just him shivering despite the environment?

His feet made their way in the rethickening layer of snow, with every step harder to take. Welp, maybe Papyrus was right about exercising. The wind blew snow under his clothes, but it was okay. He didn't have skin, nor any pain receptor to report the cold. Nor did he care about himself anymore.

He had seen timelines like this. Hundreds and hundreds time they haunted him in his sleep or in his peaceful moments. They come, they kill, they reset, they leave eternal pain and suffering for him... Every human... Every _kid._ That old lady... if she hadn't made him make a promise, none of this would have happened. _It_ is _my_ _fault, after all...This, and the other timelines too..._ That was why Sans hated promises.

As he was swimming in the bitter pool of self-loathing and responsibility, something colourful caught his attention. It was in the distance, but it looked like Papyrus's cape. _Ah, there he is._

Stupid skeleton, sitting in the snow in the middle of a blizzard... Surely, he'd just arrived too or felt bad for not being able to stop the human from killing before they got in Snowdin. Sans felt his soul warming up again, melting in his chest from relief. His brother was safe! He was alive! Papyrus was alright, safe and sound! He could only slowly make his way through the whiteness. "Oi, Pap!" He called, his voice losing in the wind.

However, as he got closer his joy evaporated immediately. "P-papyrus? No..." What he believed to be his brother was, in fact, only a big lump of dust and snow, with Papyrus's red cape.

 _It can be just a regular red piece of clothing. This can be anyone here. This pile of nothingness can't be my brother!_ _No way!_ But deep inside he knew. The touch of the material, other smaller pieces... all of them were too familiar for him. He was the one who helped his brother making them.

Sans fell to his knees, holding onto the soft, strawberry-coloured textile. It was dusty too. "No..." He clenched his fists and shut his eyes tightly. His whole world was falling apart and this time it wasn't a dream. It was real and painful and lethal.

The short skeleton opened his eyes, seeing half of the world in blue, as his left eye flared up. He coldly cracked a smile and a low, humorless laugh bubbled up from his chest. If that's the way they want to play...

Sans was like a wounded animal. Hurt, dangerous, bloodthirsty. However, mental wounds heal slower than physical ones.

 _Papyrus always believed in second chances. He used say: "Sans, even the worst person can change, if they just try!" I bet he dug his own grave with this thinking..._

"I hate break it for you, Pap, but..." Sans began, as he tied his brother's cape around his neck as a scarf. It covered half of his face, muffling his words. "That human... they gonna have a bad time for this, I swear upon my soul."

xXXx

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 **A/N: Thanks for reading, I always wondered how did Genocide Sans feel when he found his brother dead, so I wrote this instead of sleeping.**

 **I'm not sure in my grammar at all, so please, feel free to correct me and tell me your opinion about it!**

 **I hoped that at least I could manage to capture Sans's personality and reflect his feeling... A bit... I know I'm not really good at show and tell.**

 **Update: Since I wrote this, I got to know them better, and I know that Papyrus is aware of the timelines as well. But it doesn't really matter because Sans is the one who tries everything to protect his world.**


End file.
